Witty Pi 4: No Power On After Missed Alarm Without Power

I'm using a Witty Pi 4 with Raspberry Pi 3B. Debian Bookworm-based Raspberry Pi OS Lite 32-bit. I am not using the Witty Pi bash script software, but have ported the routines to Python for better integration with my custom application software. The system works well normally, waking up every 2 hours with ALARM1 to perform some work reading sensors and transmitting data, then shutting the system down with `shutdown -h now`. I am not using any of the low-voltage or temperature thresholds, and do not schedule a shutdown alarm. The system is powered by a 12V LiFePO3 battery via the header connector on the Witty Pi 4.

If the battery dies and some amount of time passes, so that ALARM1 was never run, then when I reconnect a new battery the Witty Pi 4 does not wake the RPi up. Power is reconnected, I see the ~5 second blink LED on the Witty Pi showing that it has power, but it does not wake the Raspberry Pi. 

My understanding from the user manual is that the Witty Pi should wake the RPi with reason 8 = "ALARM1 delayed", so that my software can schedule the next future ALARM1 time. But this isn't happening.

My Python code clears these flags at shutdown time before running `shutdown -h now`:

ctrl2 = _i2c_read(RTC_CTRL2)
ctrl2 = ctrl2 & 0xBF  # Clear bit 6 (alarm flag bit)
_i2c_write(RTC_CTRL2, ctrl2)
_i2c_write(CONF_FLAG_ALARM1, 0)
_i2c_write(CONF_FLAG_ALARM2, 0)

Is there something else I should be doing to manage statefulness to ensure that the Witty Pi wakes my RPi when power is reapplied, after power has been completely disconnected for a long period of time?